Mimulus Moschatus Dougl
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New England Plant Conservation Program Conservation and Research Plan Mimulus moschatus Dougl. ex Lindl. Musk Flower Prepared by: Bayard C. Ewing Antioch New England Graduate School Keene, New Hampshire For: New England Wild Flower Society 180 Hemenway Road Framingham, MA 01701 508/877-7630 e-mail: [email protected] • website: www.newfs.org through a cooperative agreement with the United States Fish and Wildlife Service Silvio O. Conte National Fish and Wildlife Refuge Approved, Regional Advisory Council, May 2001 SUMMARY Mimulus moschatus Dougl. ex Lindl.(Musk flower) is a short-lived perennial herb in the Schrophulariaceae (Figwort) family often found in cool wet soil. It is relatively common in the western United States (California and the Rocky Mountains) north to Western Canada. In the east, it occurs from the Central Atlantic states north through New England. In New England, the species is listed as Division 2 by the Flora Conservanda: New England (Brumback and Mehrhoff et al. 1996). Division 2 taxa have fewer than 20 current occurrences (since 1970) in New England: four in Massachusetts, six in Vermont and three in New Hampshire. Factors contributing to the rarity of this species include: limited habitat; exotic species; human manipulation of hydrology; and habitat succession. There has never been agreement as to whether the taxon is a true native in New England. In the early 19th century, it was collected in the West, cultivated in Great Britain, and later cultivated in Eastern Canada and New England. Since it was first officially documented in New England in 1902, it has not been clear whether the populations found were native plants or escaped cultivars. Even botanists who believe that the species is native to New England tend to feel that certain populations may be native and others may be introduced. For that reason, this conservation plan recommends that DNA and morphological research be conducted to determine which populations are native and which are escaped from cultivation before any of the costly or time consuming recommendations of this plan are implemented. Mimulus moschatus is rare in New England due to its specialized habitat requirements. It is found along watercourses and also sometimes appears in disturbed sites such as ditches and roadsides. Natural threats to this species are natural succession of open areas to shrub and forest communities, vulnerability to environmental stress, particularly to drought and soil instability. Human threats include development, recreation, road management and manipulation of hydrology. Additionally, Mimulus moschatus is not a strong competitor and is subject to threats from exotic invasive plants. If DNA research indicates that the listed populations of this taxon are native, the primary conservation objective will be to maintain a minimum of 15 occurrences of Mimulus moschatus in New England over the next 20 years. This number of occurrences would recreate the historic number and distribution of this taxon in the region. Since the number of individual plants in populations of this taxon appears to vary widely from year to year, at least seven of the fifteen occurrences should be maintained at a level of greater than 200 hundred individuals. To accomplish this objective, it will be important to: better characterize the taxons distribution in Connecticut and Maine (where it is currently considered exotic); implement immediate efforts to protect current occurrences from invasive exotic plants; maintain a viable seed bank; document ownership of each occurrence; reintroduce occurrences at appropriate historic sites; survey known occurrences which have not been recently surveyed; and survey to find undocumented and historic occurrences. i PREFACE This document is an excerpt of a New England Plant Conservation Program (NEPCoP) Conservation and Research Plan. Full plans with complete and sensitive information are made available to conservation organizations, government agencies, and individuals with responsibility for rare plant conservation. This excerpt contains general information on the species biology, ecology, and distribution of rare plant species in New England. The New England Plant Conservation Program (NEPCoP) is a voluntary association of private organizations and government agencies in each of the six states of New England, interested in working together to protect from extirpation, and promote the recovery of the endangered flora of the region. In 1996, NEPCoP published "Flora Conservanda: New England," which listed the plants in need of conservation in the region. NEPCoP regional plant Conservation Plans recommend actions that should lead to the conservation of Flora Conservanda species. These recommendations derive from a voluntary collaboration of planning partners, and their implementation is contingent on the commitment of federal, state, local, and private conservation organizations. NEPCoP Conservation Plans do not necessarily represent the official position or approval of all state task forces or NEPCoP member organizations; they do, however, represent a consensus of NEPCoP's Regional Advisory Council. NEPCoP Conservation Plans are subject to modification as dictated by new findings, changes in species status, and the accomplishment of conservation actions. Completion of the NEPCoP Conservation and Research Plans was made possible by a generous funding from an anonymous source and data were provided by state Natural Heritage Programs. NEPCoP gratefully acknowledges the permission and cooperation of many private and public landowners who granted access to their land for plant monitoring and data collection. This document should be cited as follows: Ewing, B. C. 2001. Mimulus moschatus (Musk Flower) Conservation and Research Plan. New England Wild Flower Society, Framingham, Massachusetts, USA. http://www.newfs.org. © 2001 New England Wild Flower Society ii I. BACKGROUND INTRODUCTION Mimulus moschatus Dougl. ex. Lindl. (Musk Flower) is a short-lived perennial herb in the Schrophulariaceae (Figwort) family, often found in cool wet soil along brooks, springs and wet seeps. It is relatively common in the western United States (California and the Rocky Mountains) north to British Columbia and Western Canada. In the east, it occurs from the Central Atlantic states north through New England. In 1996, the New England Plant Conservation Program (NEPCoP) with information provided by the state Natural Heritage Programs, developed a regional list of endangered plant species. Mimulus moschatus is listed as Division 2 in Flora Conservanda: New England (Brumback and Mehrhoff et al. 1996). The Flora Conservanda reported 13 documented occurrences of Mimulus moschatus in New England since 1970 (Brumback and Mehrhoff et. al. 1996). These occurrences, presently considered to be native by the Natural Heritage Programs in each state, are located in Vermont (6), New Hampshire (3) and Massachusetts (4). The Flora Conservanda listed the taxon as historic in Connecticut, but the Natural Heritage Program has since changed the designation to exotic (Les Mehrhoff, Torrey Herbarium, personal communication). The Maine Natural Areas Program considers all its occurrences introduced. The 1980 Flora of Oxford County Maine (Campbell and Eastman 1980) notes a single collection of this species in 1941 by Adams in the town of Hartford. An asterisk, indicating it is adventive, introduced by man and escaping from cultivation, precedes the entry for this taxon. There is considerable disagreement as to whether Mimulus moschatus is a true native to New England. It was first discovered by David Douglas growing around springs in the Columbia River region of western North America. Primarily because of its musky scent, it was introduced to England in 1827 (Syndenham 1827). It was later introduced into eastern North America for the same reason (Saunders 1933). However, because all the plants in cultivation lost their musky scent, the flower fell out of favor as a cultivated plant (Tucker 1988). The earliest official documentation of Mimulus moschatus in New England was made by M. E. Ward who found it growing in a "spring on a roadside bank, growing in trickling water" in Warwick, Massachusetts in 1902 (Ward 1904). Prior to the formation of the Rocky Mountains, one continuous temperate forest stretched across Canada and the United States from the east to the west coast. The orogeny of the Rocky Mountains thirty million years ago cast a rain-shadow over the Great Plains, and the dry conditions eliminated this forest from the center of the continent. As a result, there are many 1 examples of plant genera in addition to Mimulus that have distinct but related eastern and western species. Examples of this are flowering dogwood (Cornus florida) and pacific dogwood (Cornus nuttallii), sugar maple (Acer saccharum) and big-leaf maple (Acer macrophyllum)(Whitney 1989). The fundamental question regarding Mimulus moschatus is whether the populations found in the east are genetically differentiated from those in the west. Before any major efforts are made to protect and restore this taxon in New England, DNA studies should be made of the all the eastern populations and compared with western populations to make this determination. If eastern populations are not significantly different from those in the west, we must assume that our populations are introduced and should be classified as exotic. If the studies show that some or all of our local populations are genetically distinct, then it is recommended that this